Researchers are well along in designing a highly efficient, inexpensive solar cell, but the big barrier to the dissemination of solar power in society remains the problem of installation, says Marc Baldo. As an engineer, Baldo expresses confidence that “we’re going to mow down” the problem of producing a great solar cell and making it cheap. His own lab has developed a unique approach that’s found enthusiastic support from the federal government and others. Unlike conventional solar cells that use a single material such as silicon to perform both functions of absorbing light and converting it into electricity, Baldo’s cell “separates the functions and optimizes both.” His solar concentrator utilizes inexpensive material like glass or plastic onto which a thin film of dye has been painted. Sunlight strikes this surface, and the dye, which can be “tuned” or colored to trap specific wavelengths of light, emits light back to solar cells along the edge of the plate. There are enormous advantages derived from this design: The glass or plastic (considerably cheaper than silicon) catches diffuse light, so there’s no need to track the sun, and it concentrates the sunlight much more efficiently than conventional solar cells.  But solar concentrators alone don’t signal the start of a new solar age. Baldo addresses the considerable uncertainty around the broad deployment of solar power. Installation costs for single homes appear formidably high, perhaps 2/3rd the cost of the entire system. Colossal solar fields that might replace fossil fuel burning plants must ship their energy across vast distances, losing electricity along the way. And right now the national power grid isn’t set up to handle the fluctuations in energy that large-scale intermittent energy sources such as solar or wind present. Clouds are a “big pain” for grid operators, says Baldo. He believes the best start for solar will be in commercial and industrial installations such as the rooftops of facto...